The present invention relates generally to the field of printed circuit boards, and, more particularly, to component packaging on a printed circuit board.
Modern high performance computers contain a number of printed circuit boards (PCB) to carry and interconnect the various integrated circuit chips and other components that make up the computer system. Computers may be configured to have one or more subsystems, each in its own right a computer, that are interconnected into a larger, greater capacity computer. Each subsystem may contain basically the same components assembled in a chassis. Within a given subsystem, there may be, among others, a processor board, a power board, and any number of secondary or daughter boards that are carried upon a support structure within the subsystem chassis. These subsystems of boards are carried in racks in the computer chassis.
Processor boards are so named as they contain one or more processors, or central processing units (CPU). The CPU is an integrated circuit (IC) chip that is considered the xe2x80x9cbrainsxe2x80x9d of the computer. The processor board serves as a communication medium for the exchange of electrical signals among the one or more attached processors and other electrical components attached to the processor board, daughter cards, and other components. The processor board is commonly referred to as a backplane, mother board, system board, or mainboard, depending on its finction and configuration.
The processor board is a printed circuit board. A PCB is a relatively thin, flat sheet structure. The PCB may be made of laminations of reinforced fiberglass or plastic and metallic interconnects which electrically link the components attached to the board.
Processor boards contain one or more processors. Some processors are actually an assembly consisting of a processor module and a power conditioning module. These assemblies are relatively large, taking up considerable surface area of the processor board. Even though the assembly""s corresponding electrical contact pins require considerably less PCB surface area, the physical dimension of the assembly requires considerable PCB surface area if attached to the PCB using conventional methods. Careful placement consideration of other components is also a factor, considering that component to component distances must be minimized.
Additionally, for a given printed circuit board size, the large processor assemblies take up considerable surface area of the board. In some cases, components which are typically attached to the PCB in close proximity to the processor, are moved to other locations on the board or moved entirely off the board onto daughter boards. As a consequence, the distances between electrical components become large which is detrimental to the performance of the system as a whole.
Another electronic component attached to the processor board is an IC chip set commonly known as the HUB. The HUB controls the computer""s electrical components such as, among others, the one or more processors, the memory, and the communication between other PCBs and to external peripherals. In the recent past, processor board configurations provided for one processor controlled by one HUB. In order to increase the performance of a computer, designers have added additional processors on a single processor board creating multiple processor computers. A limitation to a computer""s performance, among others, is caused by the distance between electrical components, and in particular, the distance between the HUB and the one or more processors. As these distances become greater, the performance of the computer is compromised.
Another consideration in computer processor board design is in the cost of manufacture. The cost of tooling and producing PCB""s of different sizes and configurations is a cost burden. The PCB designer is economically encouraged to design PCB which require a minimal amount of retooling.
There is a need in the art for a PCB configuration of the electrical components to minimize the distance between the HUB and the one or more processors. Further, there is a need for a PCB configuration such that PCB utilization of surface area is maximized for a given PCB size. Additionally, there is a need for a PCB configuration that can be economical to produce for different computer configurations using substantially the same PCB configuration, to provide for economy of manufacturing. The packaging of such assemblies requires consideration of cooling, power, mechanical placement, electrical specification and cost. The overwhelming size of the new generation of processors compared with previous generations of processors presents a unique challenge to PCB configuration and packaging.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an improved method of PCB component configuration to address the challenges of minimizing the distance between electrical components and to relieve manufacturing cost burdens.
The above-mentioned disadvantages associated with large processors mounted on printed circuit boards, and other disadvantages, are addressed by the present invention and will be understood by reading and studying the following specification.
New apparatus, methods and configurations are provided that allows for a minimizing interconnect distances between the HUB and the one or more processors. The configuration and methods include placing the processors on one side of the processor board and the HUB placed on the opposite side of the processor board and in close proximity to the processor electrical leads. This enables the interconnection distance between the processor leads and HUB leads to be minimized and not restricted by the physical size of the processor and HUB housings.
In particular, an illustrative embodiment of the present invention includes a printed circuit board (PCB) having a plurality of apertures piercing through the PCB, wherein electrical leads of electrical components may pass through and be soldered. The PCB has a top surface and a bottom surface. The pattern of apertures on either side is substantially the same as the apertures pierce through the PCB. A plurality of groupings of apertures corresponding to the electrical lead patterns of larger electronic components are provided. Specifically, two HUB-chip conductive portions are provided, each HUB-chip conductive portion adapted to receive a HUB-chip. Additionally, four processor-chip conductive portions are provided. Each processor-chip conductive portion is adapted to receive a processor-chip. Two processor-chip conductive portions are disposed on opposite sides of each HUB-chip conductive portion in a symmetrical, mirror image arrangement.
Each processor-chip conductive portion has a plurality of terminating resistor conductive portions positioned around three sides of the processor-chip conductive portion. Terminating resistor conductive portions are adapted for the attachment of terminating resistors.
Two HUB-chips, a plurality of terminating resistors, and various other electronic and mechanical components are attached to one side of the PCB. Four processor assemblies are attached to the converse side of the PCB.
In one embodiment of the present invention, the apertures and conductive portions on the left half of the PCB are a mirror image of the apertures and conductive portions on the PCB right half. In one embodiment of the invention for a PCB adapted for four processors, a plurality of electrical paths between the PCB left half and the PCB right half are provided for necessary electronic exchange.
In another embodiment of the present invention, the PCB is adapted to be severed about the junction of the left half and the right half of the PCB. The PCB does not have interconnected electrical paths between the left and right halves of the PCB, allowing for the PCB to be severed to produce two two-processor printed circuit boards.